if you have used key mapping and changed your keys around
do a search in the settings subfolder for any files named
keymap.cfg
keymapping.cfg
keyboard.cfg
if my memory serves correctly, it is one of these names
just delete it and it should all go back to normal.......
I do not currently have any key mapping in use on my system, and was unable to find the specific file......
give it a shot, if it is there then give it a go.......
I'll do another search just incase I am informing you wrong.....